<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
  .fa{
    margin:100px;
    width: 200px;
    height: 200px;
    background-color: #bfa;

  }
  .son{
    position: relative;
    right: 20px;
    left: 20px;
    top:20px;
    width: 100px;
    height: 100px;
    background-color: burlywood;
  }
  .bro{
    width:100px;
    height: 100px;
    background-color: black;
    float: left;
  }
</style>
</head>
<body>
  <div class="fa">
    <div class="son"></div>
    <div class="bro"></div>
  </div>
</body>
</html>